I just bought a '98 2dr Blazer LS with 138,400 miles. One issue that I've noticed after driving it for a few days is that on rough roads I'm seeing the interior light flicker on. This is the overhead light in the ceiling and a light in the passenger footwell. Both doors seem to be shut tight so there appears to be some intermittence in the wiring. Wondering if this is a common issue. We used to have a '99 4dr LT and never had this sort of issue.

Discovered today that this does respond to the dome light over-ride switch so at least I think I know how the temper the effects of this but I'd still like to get to the bottom of it.

 

I would start searching around for a short.

 

Just wanted to update this issue.

After driving the new (to me) Blazer for a few days and having the passenger door opened and closed a bunch of times when I drove my kids in it, whatever was causing the flicker has cleared itself. I think it was probably something with the switch on the passenger side since prior to this, the only activity on the passenger door in the past few months had probably been when I test drove it.

 

Maybe the switch on the passenger door was released enough to be off, but when you hit a bump, it would make contact and turn them on. Glad it has cleared itself.